The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Laser welding has been known and used in the automotive industry, as well as other industries, for some time. Generally, it is known to use lasers to weld steel plates together. It is common to coat these steel plates with a protective coating that inhibits rust and other materials that reduce the useful life of the plates. The use of coatings, such as a zinc coating, for example, results in the plates being galvanized or galvannealed. The use of a coating on the plates, however, causes problems when welding the plates together. That is, the boiling temperature of materials used to coat the plates is different than a melting temperature of the steel used in the plates. As such, when welding the coated plates together, the coating may boil and infiltrate the molten pool of the weld and cause it to spatter, become porous, or both. The spattering and porousness of the weld results in the weld being mechanically weak and prone to corrosion.
To overcome the infiltration of the coating into the molten pool it is common to weld the coated plates together when they are separated from each other by a gap. This gap assists the coating in its gaseous form to be expelled through the gap away from the molten pool. Notwithstanding, the use of a gap is impractical due to increases in manufacturing time and cost.
Accordingly, there is a need for an improved laser welding system that reduces spattering and porous welds that are caused by the coating of the plates infiltrating the molten pool of the weld and causing the weld to spatter or become porous. Moreover, it is desirable to be able to weld a pair of coated plates together without having any gap between them.